1. Field of the Invention
The present invention is directed to power delivery systems. More particularly, the present invention is directed to an apparatus that facilitates the measuring and testing of electrical power present in a circuit or delivered to a device and a method for assembling the apparatus.
2. Background of the Invention
While systems to monitor power characteristics of an electrical circuit have been proposed in the past, all of those systems suffered from shortcomings that prevented them from successful deployment in critical applications.
Most of the prior art devices cannot be used to measure current because any current measuring device placed over all of the conductors would result in an inaccurate reading of current because the power passing through the conductors would be out of phase and would result in a reading of nearly zero current flow.
U.S. Pat. No. 3,206,707 to Lo Vetere discloses an electronic circuit testing apparatus. The Lo Vetere apparatus is used for servicing tube-type radio and television sets. Lo Vetere teaches a length of insulated conductor having a bare uninsulated portion referred to as a breakout lead, and an insulating tubular sleeve frictionally fitted around the insulated conductor that can be slid along the conductor for covering and uncovering the bare insulated portion. See FIGS. 1 and 3 of Lo Vetere. The purpose of the Lo Vetere invention is to conveniently expose, disconnect, and reconnect live wires for test leads at point 3xe2x80x943. See FIG. 1. This is also discussed in column 2, lines 59-67. The breakout lead of the ""707 patent is attached to electronic tube sockets. This system, with energized bare conductors, would be unacceptable for any critical hardware. Use of the breakout lead could easily short-out the leads causing disruption of electrical service to the critical hardware. If any part of the monitoring circuitry failed, it could cause the power to fail, thus causing the critical hardware to fail.
The device disclosed in U.S. Pat. No. 3,206,707 is a testing device used for tube-type radio and television components like tubes, capacitors, resistors. See column 1, lines 30-37. It also connects to bare leads. The device disclosed in the ""707 could not be used in a critical situations. The exposed wire leads and lack of mechanical protection of the conductors would likely cause short circuits.
This device is for use by trained technicians who would not be endangered by the exposed energized electrical leads. Because of the inherent danger of the easily exposed conductors, the apparatus must not be installed permanently in populated areas. (National Electrical Code: Article 110-27 xe2x80x9cGuarding of Live Partsxe2x80x9d)
U.S. Pat. No. 3,559,200 to Walters discloses a monitoring unit for signaling a specific condition in the circuitry supplying power to an electrical device. This patent monitors and records voltage used by an electrical device and takes action on the results.
The monitoring unit according to the ""200 patent has electronic components attached to the power source that directly feed the critical hardware. If any part of the monitoring circuitry fails, it could cause the power to fail, thus causing any hardware to fail. The electronic components used in this device are part of the device and as such will become obsolete as time passes. The device disclosed in the Walters patent does not allow the removal or reinstallation of the metering and test equipment without interrupting the critical power supply.
The internal electronic circuitry of the apparatus uses the same electrical source that supplies the appliance being monitored. This can influence and affect the power delivered to the appliance. There are also discrete electrical connections shown in FIG. 4: conductor P and conductor 18 are connected; conductor G and conductor 19 are connected; and conductor N and conductor 20 are connected. These connections would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. The failure could even cause a short circuit and disrupt the power.
U.S. Pat. No. 3,878,458 to Muska discloses an electrical safety test apparatus for detecting leakage, current-tripping current and proper grounding. Muska U.S. Pat. No. 3,878,458 discloses a device designed for ground fault interruption. The apparatus is the forerunner of the receptacle commonly seen in bathrooms today. It uses, for its control circuit, the same electrical source that supplies the appliance being served. In doing so there are discrete electrical connections to conductors 25, 26, and 27.
This patent has electronic components attached to the power source that directly feed the critical hardware. If any part of the monitoring circuitry fails, it could cause the power to fail, thus causing the any hardware connected to it to fail as well. In contrast to the present invention, this device is specifically designed to interrupt power. The apparatus disclosed in the ""458 patent does not allow metering and test equipment removal or reinstallation without interrupting the critical power supply.
U.S. Pat. No. 3,990,003 to Agee discloses a pulsed available conductor antenna-conduit electromagnetic radiator test technique for electromagnetic-shielding flaw detection in buried conduits and shielded conductors.
The electronic circuit testing apparatus disclosed in this patent is used for detecting buried conduit shielding flaws. The ""003 patent does not have any provision to measure current or provide a place to install a current meter. This device only detects flaws in the outer metal covering (pipe or shield). A small antenna wire is installed in the pipe or cable assembly at the time of construction. The device reads the broadcast signal from this antenna wire through the side wall casing of the pipe or metal shield detecting flaws in the outer covering.
U.S. Pat. No. 4,182,982 to Wolf discloses a current-sensing transducer for power line current measurements. The device disclosed in the ""982 patent is a current divider that is used to measure large magnitudes of AC current. Electric utilities use this device to meter industrial and commercial buildings. These types of devices are designed and built for specific needs and installed in locations locked away from the public. Once installed, these devices cannot be altered, removed or re-installed with the power on.
The transducer does not directly measure the current through the tested power line. Instead, the disclosed device estimates the total power by measuring only a small portion of the power traveling through a power line. This is because the total power is mechanically split, and the Wolf ""982 device must then estimate the total power by measuring the power in the portion that has been split off of the main power line.
The Wolf ""982 device also includes conductors in the power circuit. In column 7 lines 29 to 32, Wolf states: xe2x80x9cThe conductors 31 and 32 are connected to opposite terminal ends 75 of the conductive member 72 and the conductors 33 and 34 are connected to opposite terminal ends 75 of the conductive member 74.xe2x80x9d Wolf also teaches components disposed between the conductors. In the Abstract, Wolf teaches: xe2x80x9cA current-sensing transducer includes a conductive current divider including a branch path for conduction a fractional current proportional to a current to be sensed and being applied through the divider. A compensated transformer includes a primary circuit responsive to the fractional current and two secondary windings.xe2x80x9d These connections would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power.
U.S. Pat. No. 4,240,059 to Wolf discloses a current divider for a current sensing transducer. The device disclosed in the ""059 patent is a current divider for use in connection with a measurement of large magnitudes of AC current. Electric utilities use this device inside the typical glass meters used on homes. They are designed and built for specific needs and installed in locations sealed from the public. In other words, the Wolf ""059 device is not designed to permit interaction with anyone else, other than electricians deployed by the utility company. These devices cannot be altered or tampered with by the general public particularly with the power on.
In addition, the device also includes exposed energized surfaces. In column 5, lines 22-25, Wolf states: xe2x80x9cthe pair of hot line conductors have the voltage V, typically 240 volts, 60 Hz., there across with the line currents I1 and I1xe2x80x2 passing in series with two power line conductors.xe2x80x9d Again in column 6, lines 36-38, Wolf teaches: xe2x80x9ca current divider of this configuration may be stamped from a sheet of any suitable conductive material such as copper or aluminum.xe2x80x9d The exposed energized surfaces of this apparatus cannot be installed permanently in areas where people are present. See National Electrical Code: Article 110-27 xe2x80x9cGuarding of Live Parts.xe2x80x9d
The Wolf ""059 device also splits or divides the current mechanically. See Abstract: xe2x80x9cA current divider having two major current paths and a shunting current path.xe2x80x9d Since the Wolf ""059 device must estimate the total power based on only a portion of the total power, the device provides a much less accurate indication of electrical activity than a direct reading.
In addition, a current-divider device like Wolf ""059 would force the use of a non-standard measuring device. The current-divider would need a measuring device specifically designed to work with it. The meter would have to increase the reading by the amount of the division. For example, if the current-divider passed 25% of the current through its meter section, the meter-reading device would have to multiply the reading by 4 to get the total reading. These types of devices would not permit the use of different meters by different people. Also, it would be impossible to use standard meters because all standard meters are based on a 1-to-1 ratio. The fact that it has exposed electrical surfaces would make it dangerous not only to the people, but to the critical equipment it would serve. This device is mainly for use by an electric utility.
U.S. Pat. No. 4,250,449 to Shum discloses a digital electric energy measuring circuit. The device disclosed in this patent monitors and records voltage and amperage used by an appliance and takes action on the results. The internal electronic circuitry of the apparatus uses the same electrical source that supplies the appliance being monitored. There are discrete electrical connections, conductor 12 at point 21, and conductor 13 at point 20. See FIG. 1. These connections would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, this could change the quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power.
Shum""s device is a digital electric energy measuring circuit. It can only be read visually. The measurements cannot be sent to a computer or any other monitoring device. The device also does not allow its removal or reinstallation without interrupting the critical power supply.
U.S. Pat. No. 4,253,151 to Bouve discloses an apparatus for monitoring and controlling consumer power consumption. This patent monitors and records voltage and amperage used by an appliance and takes action on the results. The Bouve device has electronic components attached to the power source that directly feed the critical hardware. The internal electronic circuitry of the apparatus uses the same electrical source that supplies the appliance being monitored. There are discrete electrical connections. See column 7, lines 29 to 31 xe2x80x9cIt is noted that power to the circuits of the apparatus is itself derived from the plug 134 by means of a conventional rectifier (not shown).xe2x80x9d This connection would impose an additional point of failure on the circuit. If for any reason any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power.
Like other prior art devices, Bouve""s device does not permit removal or reinstallation without interrupting the critical power supply and the device can only be read visually.
U.S. Pat. No. 4,417,196 to Cueto discloses a cord set with power-factor control. The apparatus disclosed in the Cueto patent is a device designed for power-conservation. The apparatus uses for its control circuit the same electrical source that supplies the appliance being served. In doing so there are discrete electrical connections between electronic components and conductors 13, 14, and 15.
The electronic components connected in series between the common power source and the output connections to the consuming appliance are: Voltage Detector (20), Current Detector (21), Phase Detector (22), Control Circuit (23), Heat Sinks (26). If, for any reason, any of these electronic components should fail the result could change quality or characteristic of the incoming electrical power or open the circuit to the critical consuming device.
The Control Circuit (23) is inherently designed to modify the output power to the consuming device. This modification is not intended to be beneficial to the consuming device, but rather to supply the least possible power to the device in order to conserve power.
U.S. Pat. No. 4,438,396 to Harnden, Jr. discloses a low cost volt/ampere meter with liquid crystal display. Harnden, Jr. discloses a device that measures electrical current and voltage. The apparatus uses, for its power needs, the same electrical source that supplies the appliance being measured. In doing so there are discrete electrical connections to conductor 31a and conductor 31b as shown in FIGS. 1 and 2 of Harnden. See also column 3, lines 9-19. This connection would impose an additional point of failure into the circuit. If, for any reason, any electronic component should fail the result could change quality or characteristic of the incoming electrical power. It could even cause a short-circuit and disrupt the power altogether.
The electronic components used in this device are part of the device and as such will become obsolete as time passes. Other products do the measuring. As better metering equipment becomes available, they can be installed on the present invention without disrupting the power supply to the critical equipment. The Harden device also does not allow its removal or reinstallation without interrupting the critical power supply.
U.S. Pat. No. 4,492,919 to Milkovic discloses a current sensor. Milkovic discloses a permanently-installed device to measure large amounts of current. The Milkovic device is a current divider for use in connection with a measurement of large magnitudes of AC current.
The Milkovic device has exposed energized surfaces. In column 2, lines 65-67, Milkovic states: xe2x80x9cFIG. 2. Current sensor 10 utilizes a member 11 of a conductive material, such as copper and the like.xe2x80x9d The exposed energized electrical surfaces is also shown in items 1 2 and 2a (see FIG. 1); items 11, 11a, 11b, 11c, 11d, 12a, 12b (see FIGS. 2 and 2a); items 40, 40a, 40b, 40-3 (see FIG. 2b). These exposed surfaces are inherently dangerous. The exposed energized surfaces of this apparatus must not be installed permanently in areas populated by people. (National Electrical Code: Article 110-27 xe2x80x9cGuarding of Live Parts.xe2x80x9d)
Column 4, lines 33-39 states: xe2x80x9cThe current I2 flowing in sensing-branch member 14 is sensed by a current transformer 16. The transformer utilizes element 14 as a single-turn primary winding passing through a core 16a upon which a multi-turn secondary winding 16b is wound. Transformer 16 is placed about member 14 prior to the installation and fastening of the latter within slots 11g.xe2x80x9d Also, column 5, second paragraph states: xe2x80x9cThis analog AC output voltage V0 can be directly utilized, or can be converted to digital data by means of an analog-to-digital converter 26 having its input connected to terminal 24a.xe2x80x9d From those portions, it is clear that the Milkovic device includes electrical components connected directly to the critical power circuit. If those components were to fail, they could interrupt the power delivered in the power circuit.
The Milkovic device also splits or divides the current mechanically. Because of this, the Milkovic device would suffer from the same disadvantages as Wolf ""059, discussed above.
U.S. Pat. No. 4,496,932 to Halder discloses a current divider for current measurement in conjunction with a measurement transducer. The device disclosed in the Halder patent is a permanently installed device to measure large amounts of current. The patent does not allow the metering and test equipment to be removed or reinstalled without interrupting the critical power supply. In addition, Halder includes exposed energized surfaces. See column 3, lines 64-68. This device is not suitable for use where people are present.
U.S. Pat. No. 4,732,566 to Martucci discloses an electrocution proof line and extension cord. The patent includes features that attempt to prevent electrocutions due to improper wiring. The present invention is diametrically opposed in use and construction. The Martucci device is used to protect human life, while the present invention is intended to protect critical equipment. Martucci discloses an electrocution proof line and extension cord; it is not intended to be used for testing or monitoring.
U.S. Pat. No. 4,780,094 to Batty discloses an extension cord of under carpet flat cable. The Batty device is an extension cord expressly made to lie flat under carpeting. It is not used for testing or monitoring.
U.S. Pat. No. 5,285,163 to Liotta discloses an electrical cable continuity and voltage tester. The Liotta device tests whether power to stage (theatrical) lighting is on or off. The Liotta reference does not include provisions to measure the amount of current drawn. It is a self-contained digital device showing on and off only.
The internal electronic circuitry of the apparatus uses the same electrical source that supplies the appliance being monitored. There are discrete electrical connections to conductor N and conductor H. See FIG. 3. This connection would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power. Additionally, the Liotta device does not allow a technician to install current metering equipment into the circuit without power interruption.
U.S. Pat. No. 5,339,232 to Lin discloses a miniature light set and does not teach any measurement features.
U.S. Pat. No. 5,716,231 to Meeker discloses a sensor breakout lead. The sensor breakout lead is described as, xe2x80x9ca length of insulated conductor having a bare uninsulated portion, and an insulating tubular sleeve coaxially and frictionally fitted around said insulated conductor and slidably movable therealong for covering and uncovering the bare insulated portion.xe2x80x9d See column 2, lines 4-13 and FIGS. 1-3. This patented breakout lead is attached to the power source that directly feeds the critical hardware. This system with energized bare conductors would be unacceptable servicing critical hardware. If any part of the monitoring circuitry failed, it could cause the power to fail, thus causing the critical hardware to fail. The present invention has no attachment to the power supply. All testing is done through induction. 
This device is for the use of trained technicians that would not be endangered by the exposure of energized electrical leads. Because of the inherent danger of the easily exposed conductors, the apparatus must not be installed permanently in areas populated by people. (National Electrical Code: Article 110-27 xe2x80x9cGuarding of Live Partsxe2x80x9d)
The Meeker device would be unsuitable for mission-critical equipment because the device would require the mission-critical equipment to be turned off to install the Meeker device. After the testing were completed, the mission-critical equipment would have to be turned off again and disconnected from its power source. The Meeker device would be removed and then the mission-critical equipment would be reconnected from its power source. Forcing mission-critical equipment to be disconnected from its power source in order to test the power lines is exactly what the present invention is trying to eliminate.
U.S. Pat. No. 5,781,015 to Duffin discloses an extension cord with integral monitoring system. The presence of voltage lights up an LED lamp and if an attached an appliance is consuming power, the device will light up a second LED lamp. In other words, the Duffin reference teaches an indicating device.
The internal electronic circuitry of the Duffin device uses the same electrical source that supplies the appliance being monitored. There are discrete electrical connections to conductor 28 and conductor 29. See FIG. 1. This connection would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power. In addition, the Duffin reference does not allow removal or reinstallation without interrupting the critical power supply.
U.S. Pat. No. 5,811,966 to Lee discloses a meter for measuring and displaying the power consumption of an electrical appliance and the time period for the power consumption. The Lee device monitors and records voltage and amperage used by an appliance and takes action based on the results.
The internal electronic circuitry of the apparatus uses the same electrical source that supplies the appliance being monitored. There are discrete electrical connections to conductor (Neutral) and conductor (Hot) in FIG. 2. This connection would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power. In addition, the Lee device does not allow removal or reinstallation without interrupting the critical power supply.
U.S. Pat. No. 5,962,932 to Matlo discloses a power supply apparatus with circuit load sensor. Specifically, the Malto device is an extension cord with a led lamp that indicates whether power is flowing through the device. The Matlo device monitors and records voltage and amperage used by an appliance and takes action on the results. The internal electronic circuitry of the apparatus uses the same electrical source that supplies the appliance being monitored. There are discrete electrical connections to conductor 32 (Neutral) and conductor 31 (Hot) in sheet 1 of 2. This connection would impose an additional point of failure on the circuit. If, for any reason, any electronic component should fail, the result could change quality or characteristic of the incoming electrical power. It could even cause a short circuit and disrupt the power. The Malto device does not permit the metering and test equipment to be removed or reinstalled without interrupting the critical power supply.
The present invention is directed to an apparatus that permits the electrical activity of an electrical conductor to be conveniently measured. The invention includes the use of separated conductors. The invention can assume many different embodiments. The invention includes a chassis adapted to receive a first conductor and second conductor, the first conductor being separated from the chassis and the second conductor a distance sufficient to accommodate a portable, handheld current-sensing device. The first conductor has an insulating jacket and is generally less flexible than the flexibility of the first conductor without the insulating jacket. In addition, the invention preferably does not influence the current flow through the apparatus and the invention continues to provide electricity even if the current detector malfunctions.
In one aspect, the invention provides an outer shell adapted to retain a conductor comprising a base adapted to associate with a support surface, a hollow sensing portion extending from the base and adapted to retain a conductor. The sensing portion is spaced from the base a distance sufficient to accommodate a portable, hand-held current sensing device.
In another aspect, the invention includes a first side of the base that is adapted to engage the support surface and the sensing portion extending from a second side of the base.
In another aspect, the invention includes the sensing portion includes a passage.
In another aspect, the invention includes a passage that is sized to accommodate a wire.
In another aspect, the invention includes a passage is sized to accommodate an insulated wire.
In another aspect, the invention includes a flange adapted to assist in mounting the outer shell to the support surface.
In another aspect, the invention provides a method for assembling an apparatus comprising the steps of (a) locating a first set of holes, comprising a first hole and a second hole, disposed on an outer shell, the first set of holes being associated with a sensing portion and the first set of holes in communication with a passage disposed within the sensing portion, the sensing portion being spaced from a base a distance sufficient to accommodate a portable hand-held current sensing device; (b) inserting a wire through the first hole; (c) threading the wire through the passage; and (d) extending the wire through the second hole.
In another aspect, the invention the wire is bare.
In another aspect, the invention includes the wire is insulated.
In another aspect, the invention includes a step of terminating the wire after the wire has been extended through the passage.
In another aspect, the invention includes a step of mounting the apparatus to a support surface in a manner that permits access to the sensing portion.
In another aspect, the invention includes the step of sensing the electrical activity of the wire by using a portable hand-held current sensing device.
An object of the present invention is to provide a location where current, power, or load of a circuit can be conveniently measured.
Another object of the present invention is to provide a device that has no exposed energized parts and is specifically designed to coexist with people in any environment.
Another object of the present invention is to provide a device that is totally insulated, mechanically protected and cannot cause interruption to the critical hardware while installing or removing amperage test and monitoring equipment.
Another object of the present invention is to provide a place to install amperage-metering devices without disrupting the electrical power.
Another object of the present invention is to provide a device that is not exposed to short or open circuits.
Another object of the present invention is to permit other products to do the measuring. As better metering equipment becomes available, it can be installed without disrupting the power supply to the critical equipment.
Another object of the present invention is to allow test equipment to be removed and reinstalled without disruption of the power supply to the critical hardware.
Another object of the present invention is to eliminate any attachment to the power supply that is being monitored.
Another object of the present invention is to permit test equipment to be removed and reinstalled without disruption of the power supply.
Another object of the present invention is to provide an available conductor that can move from a deployed position to a non-use position.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and advantages of the invention will be realized and attained by the structure and steps particularly pointed out in the written description, the claims and the drawings.